Process of curing brier for pipe manufacture



Patented Jan. 16, 1945 V UNITED.

' PROCESS OF CURING BRIER FOR PIPE MANUFACTURE N Drawing.

David P. Lavietes, Brooklyn, N. Y.

Application February 3, 1942, Serial No. 429,398 Y iClaim. (01.- 117-59) The invention relates to ajprocess of curing brier for pipe manufacture, andm'ore particularly to a treatment of blocks cut from the burls of rhododendron, kalmia and similar brier woods.

For some years past, brierwood found in North Africa has not been readily available in this country because of the difficulties of importation. This imported brierwood, because of climatic and other conditions at its .point of origin, is particularly adapted for use in the by nature and is highly resistant to ,charring when in use as a pipe bowl.

American-grown brier, such as-rhododendron,

.' kalmia, etc. has been found. not to give satis "factory results sincethe conditions of its growth arepnot such as to so cure or season the wood as to prevent its rapid charring or burning while a pipe is in use, and because of its tendency to warp and crack when subjected-to heat. f

blocks, the wood cut from the burls hasv to be turned, frazed and bored to give it the desired shape before final polishing and finishing, and

wastage is high if defects in the block are not discovered until during the turning and .frazing operations. I

I have found that the blocks produced from rhododendron, kalmia', etc. burls, contain acids,

and possibly resins, preventing a' proper curing or seasoning of the brierwood, and a proper treat ment making this wood highly resistant to the heat and fire to which it is subjected while a pipe is in use.

By actual production of the brierv blocks for. the manufacture of pipes in large quantities, I" have found that such wood may be so conditioned in a short time as compared with that required for the natural conditioning of the wood, which time is of unknown duration, and that wood so conditioned will approximate the qualities of the naturally cured wood so far as the procedure followed in producing pipes from such Wood and the'durability of pipes'made therefrom, are concerned.

The native brier has a grain and takes a finish;

quite as attractive as the imported brier. In fact, 'a pipe produced from native brier, when cured and seasoned .bythe process of my invention, is at least equal in appearance and durability, to pipes made from imported brier.

- The'process ofmy invention is such as to not only remove the natural acids and possibly'resins from the brier, but to prevent ,warpingand f cracking thereof during and following the treat:

In the production of pipe bowls made of brier ment, and ensure a thorough impregnation of the blocks with the chemical agent used for imparting fire retardant properties to the wood.

;10 manufacture of pipes, since it is thoroughly cured The invention consists primarily in a process 1 of 'curing brier for pipe manufacture consisting i in subjecting a block out from the rhododendron,

k'almia or other brier burl, to an aqueous solvent for acids, resins or'other soluble constituents of the wood at an elevated temperature to remove such constituents therefrom, transferring said blocks while still saturated with said solvent, to

aqueous solution containing a fire retardant agent soluble by said aqueous solvent maintained at an elevated temperature, and finally slowly drying said blocks; and in such other further steps and'practices as are hereinafter set forth and described, and more particularly pointed out in the claims hereto appended.

In the prooess of the invention, brier blocks of a size to produce the stummels are cured or seasoned 'priorto the turning, frazing and boring operations incidental to the production of the'stumrnels. This process is an artificial aging method which results in the production, in a few weeks, of a product equal, if not superior, to the natural imported brierwood.

' To accomplish this result, it is essential to remove from substantially all of the wood of the block, the acids and other soluble constituents, including possibly resins, and to impregnate substantially the entire wood of the block with a fire retardant agent. I refer to substantially the entire'wood of the block, although it is quite unimportant whether the conditions at the core of the block are the sameas more toward the surface thereof, since in-boring, this core portion is removed.

The blocks are rough hewn, according to the shape of stummel desired, thus ensuring the desired conditioning of the portion of the block constituting the stummel, particularly about the upper portion of the bowl of a pipe.

Blocks formed as above are first placed in a I barrel or tank open to atmosphere, and subjectedto a liquid solvent for the acids or other ingredients to be removed from the wood, I

.have found, in actual practice, that ordinary reservoir water, maintainedat the temperature of substantially its boiling point, is highly effective. This treatment continues for a periodof from six to ten hours, the water being brought to the boiling point aftertheimmersion of the blocks therein, and the temperature thereof, after the'water has once boiled, being maintained by the injection of live steam thereinto. Gurgitation minimizes settling of sediment upon the surface of the blocks, although this is not a matter of major importance.

Experience has shown that with the time intervals stated, the block will become saturated throughout with the water or other solvent, and a high percentage of the deleterious ingredients in the .wood will: be removed.

After-this step in;. the process, thezblocks, before there has been an opportunity for any substantial evaporation of the solvent therefrom,

particularly that portion of the solventtoward the center of the block, aresubjected'toiarbath containing in solution a fireproofing agent, specifically boric acid. The quantity of boric-acid in the solution will vary according to the charactor of the wood being treated.

The wood of blocks cut from the rhododendron burl, being soft and coarse grained as compared withthe wood of blocks cut from kalmia burls,

" not only require shorter time intervals in the treatment; but a.'1ower-boric acid' content-in the bath. Withik'almia, Iliavefound that-'aiboric acid content of approximately 25%"gives the'best results, but'with the rhododendron wood this contentmay be much lower. I have also found-"that "the immediateitransfer ofthe solvent'saturated "blocksfrom the treatment barrel or tank tothe ;boric acid bath is"pr eferable,p although" a ..delay .of. forty-eight hours. or so is not: prohibitive.

'L'While the blocks .1. are. 'in "'the'iboric" "acid? bath,

' this bath .is' maintained 1' at. the": temperature? of ;'the boiling point of water. I ,have' heretofore maintained this? temperature byimeans' ofsteam :coilsrinthe barrels"ori'tanksrsince 'this; prevents dilution "of 'izhefire retardantisolution.

Again, accordingto the character" ofifthe wood .in the blocks,. the "time :intervals bfthisfieat- -ment'may varyfrom approximatelyv fourteen to twenty hours;.ithisi ordinarily being sufiicient" to ensure the impregnation ofisubstantiallythe"entireb'lo'ck "with' the colic acid'is'olution. "This is assisted by the water withwhichi:"the""block" is saturated andi'carries the' degree"ofpenetration "or impregnation' of the boriciiacid solution to the very center of the block.

By a'roughpre-shaping of the" blocks as stated, .the penetrationi of *the boric' acid solution. to: all "portions'of the'block used in forming 'theibowl or a 'pipegin sufiicient quantity to 'secure'the 'desired fireresistant properties of this -portion..of .theboWLis assured. It has been fo'un'd'in' actual practice 'that'lwh'en' a'pipe "'bowl' has been bored, "the'pres'ence of the" boric" acid in the iinnerwall "thereof is clearlyvisible, evento the'zn'aked. eye, *beforethe "finalfini'shing of the"'bowl. Aftenthe blocks have been subjected'tolthe bo'ric .acid'bath for thenecessary period, they are removed from; the bath and allowed to dry slowly .a'ti a slightly elevated temperature, or. in. a warm room; to complete..the"'curing. or'seasoning operation. I have. found? that thisfdryingioutcper- .ation shouldtcontinue for some eight "weeks ,.or more to permit, thei'turning, Irazing and boring operations ,withoutiilikelihood or the. subsequent warping and cracking of the wood of. a pipe bowl. "This is probablydue' to the fact that with a long "curing vorseasoning operation, substantially: all "moisture isevaporated' from the wood, leaving tonly theprecipitatexof.the boric acid in themores 'z ofzthe wood.

The" "time intervals herein j',given i are: merely "approximatesince the/operation can "be: acc'ele- "IEttEdfbY the-use of; pressure .tahksi insteadoof "using'barrelsor'tanks open to atmosphere, or by well known practices for accelerating evaporation.

The time intervals stated are those which I have actually used in producing treated blocks, and 5 with a plant in continuing operation, time intervals are not factors of major importance.

I have found the use of heated baths to be essentialiinthe first two stepsof the process, but Lbelieve that the. exact temperatures of these baths is not critical so long as they are approximately .:.the boiling point of water. The temperatures v.stated arethose used with barrels or tanks open itozatmosphere. It would be possible, however,

to" use a lower temperature if subatmospheric rid-pressumnwere maintained in the barrels or tanks.

Whilel have found, in actual practice, that a $2570. solutio -ofboric acid gives the best results with harder and closer grained briers, this percentage maybe lowered when treating the wood of rhododendron burls. I believe that under some conditions; as low age, 10% solution ofboric acid "'may""befiectively used by increasing the time "intervals.

In thepractice of theprocess, the solution used 'i25fsho'uld be closely'checked at intervals of approximately two hours, and fresh boric acid added zif necessary. The-solution may be repeatedly *"used.

Ithas been found that longer time. intervals E80 are required to properly condition blocks of larger dimensions thani'smaller blocks.

","In preparing fthe.v blocks, the "burls are first carefully inspected to remove' stones and dirt, '1' an'dithen -isawed into slabs of a thickness apt iproximating the .;height 70fb100kj required for f'stummels'of'thedesired sizes. These slabs are '1theni'cut-'into'-'stripsof a width required in' the f production of stummels of "the" size permissible "'with*-the' thickness of the slab.

Skilled"'workmen"'thencut these strips into "the greatestpossib'le length, in view of imperfections in the strips.

*Inthis way a large varietyof' blocks of dif- '"ferent" sizes for" the'production of stummels of different forms; is' obtained. The-larger blocks *command relatively-much"greater prices than smaller blocks.

When'treating blocks, they "are selected according to" size, and" the time intervals vary ac- 5o"'cordingly.

"It, :is" not 'myintentionto limit the invention "to theiprecise' time"interva1s herein stated, nor to theexactborio acid'content, except approximately within the range stated. I have found *"it essential, however, to Subject the blocks to a p bathat'anelevate'd temperature .to remove acids and other ingredients therefrom and saturate the Lb'l'ocks withwater.orother solvent; to place the blocks-in aiboric acid bath'maintained at an irelevatedtemperature before the water or other solvent has had an opportunity to evaporate, and

.Tfin'al ymo. remove. the, vehicle for .the vboric acid "The specific "temperatures, percentages and 5..time intervalshereinv stated may be varied. ac-

..cor'ding. toIthebharacteristiCs. of. the brierwood Lbeing treat'ed,...arid ,the ,sized of the blocks, .so L'thatit? is not my intention. to limit the invention .to such. specific Tdeta'ils.

1, Having .Idescribed the, invention, what I claim .asnew and'desireto, have protected by' Letters I'Patent, .is:

, 'Aprocess oficuring brier for pipe manufacture consis'tingin. subjecting .a block. cut. from .the 75 rhododendron; kalmia or other brier burl, for

from six to ten hours to water maintained substantially at its boiling point to remove acids; resins or other soluble constituents therefrom, maintaining the temperature of said Water by a continuing delivery of live steam thereinto,rtransferring said blocks while still saturated with water to an aqueous solution containing boric acid i Within a range of from 10% to 25% of the volume of the bath, at an elevated temperature for a twenty hours, maintaining said solution at substantially the boiling point of water and at a substantially uniform density by subjecting same to a dry heat, and finally drying said blocks for a time interval of approximately eight weeks at a low temperature to evaporate the liquid there- DAVID P. LAV'IETES. 

